JP2002374092A - Heat dissipating radio wave absorber - Google Patents
Heat dissipating radio wave absorberInfo
- Publication number
- JP2002374092A JP2002374092A JP2001181871A JP2001181871A JP2002374092A JP 2002374092 A JP2002374092 A JP 2002374092A JP 2001181871 A JP2001181871 A JP 2001181871A JP 2001181871 A JP2001181871 A JP 2001181871A JP 2002374092 A JP2002374092 A JP 2002374092A
- Authority
- JP
- Japan
- Prior art keywords
- radio wave
- heat
- alloy powder
- powder
- wave absorber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0073—Shielding materials
- H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
- H05K9/0083—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising electro-conductive non-fibrous particles embedded in an electrically insulating supporting structure, e.g. powder, flakes, whiskers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
- H01Q17/004—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems using non-directional dissipative particles, e.g. ferrite powders
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Soft Magnetic Materials (AREA)
- Powder Metallurgy (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、情報機器や映像機
器、移動体通信機器等の電子機器に用いられる放熱性電
波吸収体に関する。より具体的には、各種電子部品にて
発生する電磁場ノイズを減衰・吸収するとともに、各種
電子部品にて発生する熱を外部へ放散する、放熱性電波
吸収体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipating radio wave absorber used for electronic equipment such as information equipment, video equipment and mobile communication equipment. More specifically, the present invention relates to a heat dissipating radio wave absorber that attenuates and absorbs electromagnetic field noise generated in various electronic components and dissipates heat generated in various electronic components to the outside.
【０００２】[0002]
【従来の技術】近年、デジタル電子機器をはじめとし
て、準マイクロ波帯（１００ＭＨｚ〜３ＧＨｚ）以上の
高周波数帯域を利用する電子機器類の普及が進んでい
る。このような電子機器においては小型化及び高性能化
が求められ、各種電子部品の高密度実装化がなされてい
る。そして、このように高密度実装化された電子機器類
においては、電子部品等にて発生する電磁波ノイズによ
る電磁波障害やその干渉、或いは発熱による特性の劣化
などの問題が生ずるおそれがあり、その対策が重要な課
題になっている。2. Description of the Related Art In recent years, electronic devices using a high frequency band of a quasi-microwave band (100 MHz to 3 GHz) or more, such as digital electronic devices, have been widely used. In such electronic devices, miniaturization and high performance are required, and high-density mounting of various electronic components is performed. In such high-density mounted electronic devices, there is a possibility that problems such as electromagnetic interference and interference due to electromagnetic noise generated in electronic components or deterioration of characteristics due to heat generation may occur. Is an important issue.
【０００３】従来、このような問題を回避すべく、電子
部品にて発生する電磁波ノイズを減衰し吸収するものと
して電波吸収体が用いられ、また、各種電子部品にて発
生する熱を外部に効果的に放散するものとして熱伝導性
シート（熱伝導性成形体）が用いられている。Conventionally, in order to avoid such problems, radio wave absorbers have been used to attenuate and absorb electromagnetic wave noise generated in electronic components. A thermally conductive sheet (a thermally conductive molded body) is used as a material that diffuses thermally.
【０００４】一方、近年の高性能な発熱性電子部品にお
いては、電磁波ノイズと熱への対策が同時に必要とさ
れ、このような場合に上述した電波吸収体と熱伝導性成
形体の双方を併用すると、複数の部材を用いることから
コストが高くなるとともに、広い装着スペースを必要と
する等の問題があった。On the other hand, recent high-performance heat-generating electronic components require measures against electromagnetic noise and heat at the same time. In such a case, both of the above-described radio wave absorber and the thermally conductive molded body are used in combination. Then, since a plurality of members are used, costs are increased, and there is a problem that a wide mounting space is required.
【０００５】そのため、１つの部材で電波吸収と放熱の
両機能を果たすものとして、特開平１１−３３５４７２
号公報において、電磁波吸収性熱伝導性シリコーンゲル
シートが提唱されている。この電磁波吸収性熱伝導性シ
リコーンゲルシートは、金属酸化物磁性体粒子と熱伝導
性充填剤とを含むシリコーンゲル組成物から形成される
ものである。For this reason, Japanese Patent Application Laid-Open No. H11-335472 discloses a single member that fulfills both functions of radio wave absorption and heat radiation.
In the publication, an electromagnetic wave absorbing heat conductive silicone gel sheet is proposed. This electromagnetic wave absorbing heat conductive silicone gel sheet is formed from a silicone gel composition containing metal oxide magnetic particles and a heat conductive filler.
【０００６】[0006]
【発明が解決しようとする課題】しかし、上記特開平１
１−３３５４７２号公報にて提唱されている電磁波吸収
性熱伝導性シリコーンゲル成形シートは、金属酸化物磁
性体粒子として用いるＭｎ−Ｚｎ（マンガン−亜鉛）系
フェライト或いはＮｉ−Ｚｎ（ニッケル−亜鉛）系フェ
ライトの熱伝導率が低いため、熱伝導性充填剤のみを分
散させている従来の熱伝導性シートと比較して熱伝導性
が低く、十分な放熱特性を有するものではなかった。However, Japanese Patent Application Laid-Open No.
The electromagnetic-wave-absorbing heat-conductive silicone gel molded sheet proposed in 1-335472 is a Mn-Zn (manganese-zinc) ferrite or Ni-Zn (nickel-zinc) used as metal oxide magnetic particles. Since the thermal conductivity of the system ferrite is low, the thermal conductivity is lower than that of the conventional thermal conductive sheet in which only the thermal conductive filler is dispersed, and the thermal conductivity is not sufficient.
【０００７】また、上記従来の電磁波吸収性熱伝導性シ
リコーンゲル成形シートは、金属酸化物磁性体としてＭ
ｎ−Ｚｎ系フェライトやＮｉ−Ｚｎ系フェライト等のス
ピネル型フェライトを用いていたため、３００ＭＨｚ以
上の高周波数帯域になるとスネークの限界（Ｓｎｏｅ
ｋ’ｓ Ｌｉｍｉｔ）と呼ばれる制約によって透磁率が
低下し、電磁波ノイズの減衰効果が小さくなるという問
題があった。In addition, the above-mentioned conventional electromagnetic wave absorbing heat conductive silicone gel molded sheet is made of M
Since spinel-type ferrites such as n-Zn-based ferrite and Ni-Zn-based ferrite have been used, the snake limit (Snoe) in a high frequency band of 300 MHz or more.
There has been a problem that the magnetic permeability is reduced due to a restriction called “k's Limit”, and the effect of attenuating electromagnetic noise is reduced.
【０００８】以下、金属酸化物磁性体と電磁波ノイズの
減衰効果について、式（１）に示すスネークの式に基づ
いて説明する。 ｆr（μ’−１）＝Ｉs・γ／３πμ0 ・・・・・・（１） （式（１）中、ｆrは共鳴周波数、μ’は複素比透磁率
の実部、γは磁気回転比、μ0は真空の透磁率、Ｉsは飽
和磁化である。） 一般に、磁性体は、高い周波数で磁化していくと、磁壁
移動、回転磁化が起こるが、ある周波数の磁気下で磁界
変化に追従できなくなり共鳴を起こす。これを共鳴周波
数ｆrという。また、磁性体は高い周波数で磁化してい
くと複素比透磁率の実部μ’が低下していくとともに、
この複素比透磁率の実部μ’の周波数に対する変化量、
すなわち複素比透磁率の虚部μ''が上昇する。そして、
電波吸収体としての利用範囲は、共鳴周波数ｆrより高
周波数側であって、かつ、複素比透磁率の虚部μ”が高
く、実部μ’が低い（μ''＞μ’となる）周波数帯域で
ある。一方、共鳴周波数ｆrから離れた周波数帯域では
透磁率が低くなり、電磁波ノイズの減衰効果が小さくな
る。Hereinafter, the metal oxide magnetic material and the effect of attenuating electromagnetic noise will be described based on the snake equation shown in equation (1). During f r (μ'-1) = I s · γ / 3πμ 0 ······ (1) ( Formula (1), f r is the resonant frequency, mu 'is the real part of the complex relative permeability, gamma is the gyromagnetic ratio, mu 0 is the permeability of vacuum, the I s is the saturation magnetization.) in general, the magnetic body, as you magnetization at a high frequency, the domain wall movement, the rotation magnetization occurs, magnetic certain frequency It becomes impossible to follow the change of the magnetic field below and causes resonance. This is called a resonance frequency fr . Also, when the magnetic material is magnetized at a high frequency, the real part μ ′ of the complex relative permeability decreases, and
The variation of the complex relative permeability with respect to the frequency of the real part μ ′,
That is, the imaginary part μ ″ of the complex relative magnetic permeability increases. And
Range of use as a wave absorber, a higher frequency side than the resonant frequency f r, and the imaginary part mu "is high complex relative magnetic permeability, a real part mu 'is low (μ''>μ' ) is a frequency band. On the other hand, magnetic permeability becomes lower in frequency bands distant from the resonant frequency f r, the attenuation effect of the electromagnetic noise is reduced.
【０００９】ここでスピネル型フェライトについて検討
してみると、スピネル型フェライトは一般に飽和磁化Ｉ
sが小さいため共鳴周波数ｆrが小さい。そして、この共
鳴周波数ｆrの値が準マイクロ波帯よりも小さいことか
ら、準マイクロ波帯以上の高周波数帯域での透磁率が低
く、電磁波ノイズの減衰効果が小さくなる。Here, a study of spinel-type ferrite reveals that spinel-type ferrite generally has a saturation magnetization I
Since s is small, the resonance frequency fr is small. Then, the value of the resonant frequency f r from less than quasi-microwave band, low permeability at quasi-microwave band or a high frequency band, the attenuation effect of the electromagnetic noise is reduced.
【００１０】そのため、上記従来の電磁波吸収性熱伝導
性シリコーンゲル成形シートは、３０〜３００ＭＨｚの
周波数帯域における電波吸収特性が良好なものとなり、
準マイクロ波帯以上の高周波数帯域において良好な電波
吸収特性を有するものではなかった。換言すれば、上記
従来の電磁波吸収性熱伝導性シリコーンゲル成形シート
は、準マイクロ波帯以上の高周波数帯域に整合したもの
ではなかった。[0010] Therefore, the above-mentioned conventional electromagnetic-wave-absorbing heat-conductive silicone gel molded sheet has good electromagnetic wave absorption characteristics in a frequency band of 30 to 300 MHz.
It did not have good radio wave absorption characteristics in the high frequency band above the quasi-microwave band. In other words, the above-mentioned conventional electromagnetic-wave-absorbing heat-conductive silicone gel molded sheet is not matched to a high frequency band equal to or higher than the quasi-microwave band.
【００１１】本発明は、上記課題を解決するためになさ
れたものであり、その目的は、優れた熱伝導性を有する
とともに、準マイクロ波帯以上の高周波数帯域において
優れた電波吸収特性を有する放熱性電波吸収体を提供す
ることにある。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to have excellent thermal conductivity and excellent radio wave absorption characteristics in a high frequency band higher than the quasi-microwave band. An object of the present invention is to provide a heat-absorbing radio wave absorber.
【００１２】[0012]
【課題を解決するための手段】上記課題を解決するため
に、請求項１に記載の発明は、有機マトリックス中に軟
磁性体粉末と熱伝導性充填剤とを含有する混合組成物
を、所定形状に成形してなる放熱性電波吸収体であっ
て、軟磁性体粉末が、Ｆｅ−Ｓｉ（鉄−ケイ素）合金粉
末であることを特徴とする。Means for Solving the Problems In order to solve the above-mentioned problems, the invention according to claim 1 is to provide a mixed composition containing a soft magnetic material powder and a thermally conductive filler in an organic matrix by a predetermined method. A heat-dissipating radio wave absorber formed into a shape, wherein the soft magnetic material powder is an Fe-Si (iron-silicon) alloy powder.
【００１３】請求項２に記載の発明は、請求項１に記載
の発明において、Ｆｅ−Ｓｉ合金粉末のケイ素含有量
が、５〜７ｗｔ％であることを特徴とする。請求項３に
記載の発明は、請求項１又は請求項２に記載の発明にお
いて、Ｆｅ−Ｓｉ合金粉末の平均粒子径が、１〜５０μ
ｍであることを特徴とする。According to a second aspect of the present invention, in the first aspect, the Fe-Si alloy powder has a silicon content of 5 to 7 wt%. According to a third aspect of the present invention, in the first or second aspect, the average particle diameter of the Fe—Si alloy powder is 1 to 50 μm.
m.
【００１４】請求項４に記載の発明は、請求項１から請
求項３のいずれか１項に記載の発明において、Ｆｅ−Ｓ
ｉ合金粉末の配合割合が、５〜７０ｖｏｌ％であること
を特徴とする。請求項５に記載の発明は、請求項１から
請求項４のいずれか１項に記載の発明において、有機マ
トリックスが、シリコーンゲルであることを特徴とす
る。According to a fourth aspect of the present invention, there is provided the method according to any one of the first to third aspects, wherein the Fe-S
The compounding ratio of the i-alloy powder is 5 to 70 vol%. According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the organic matrix is a silicone gel.
【００１５】（作用）本発明は、有機マトリックス中に
軟磁性体粉末と熱伝導性充填剤とを含有する混合組成物
を、所定形状に成形してなる放熱性電波吸収体であっ
て、軟磁性体粉末が、Ｆｅ−Ｓｉ合金粉末であることを
特徴とする。(Function) The present invention relates to a heat-dissipating radio wave absorber formed by molding a mixed composition containing a soft magnetic powder and a thermally conductive filler in an organic matrix into a predetermined shape. The magnetic powder is an Fe-Si alloy powder.
【００１６】このようにＦｅ−Ｓｉ合金粉末を軟磁性体
粉末として用いることにより、準マイクロ波帯以上の高
周波数帯域、特に１ＧＨｚ以上の高周波数帯域におい
て、優れた電波吸収特性を有する放熱性電波吸収体を実
現することができる。これは、Ｆｅ−Ｓｉ合金の共鳴周
波数ｆrの値が準マイクロ波帯に存在することから、上
述した準マイクロ波帯以上の高周波数帯における透磁率
の低下の影響が少ないためである。また、Ｆｅ−Ｓｉ合
金は上述したスピネル型フェライトと比較して熱伝導性
が良好であるため、優れた熱伝導性を有する放熱性電波
吸収体を実現することができる。なお、本発明の放熱性
電波吸収体の形状は特に限定されるものではない。By using the Fe-Si alloy powder as the soft magnetic material powder in this manner, a radiating radio wave having excellent radio wave absorption characteristics in a high frequency band above the quasi-microwave band, particularly in a high frequency band above 1 GHz. An absorber can be realized. This is because the value of the resonant frequency f r of the Fe-Si alloy is present in the quasi-microwave band, because there is less influence of the reduction in permeability at high frequencies of more quasi-microwave band as described above. Further, since the Fe—Si alloy has better thermal conductivity than the above-described spinel type ferrite, a heat-radiating radio wave absorber having excellent thermal conductivity can be realized. The shape of the heat-dissipating radio wave absorber of the present invention is not particularly limited.
【００１７】Ｆｅ−Ｓｉ合金粉末のケイ素含有量は、５
〜７ｗｔ％であることが好ましい。ケイ素含有量が５ｗ
ｔ％未満であると、酸素などによって腐食されやすく、
電波吸収性特性及び熱伝導性が低下するため好ましくな
い。一方、ケイ素含有量が７ｗｔ％を超えると、Ｆｅ−
Ｓｉ合金粉末が硬く脆くなり、加工し難くなるため好ま
しくない。なお、Ｆｅ−Ｓｉ合金は、ケイ素含有量が６
ｗｔ％程度で、結晶磁気異方性と磁歪定数が共に０に近
くなり、高い透磁率を示すことが報告されている（本間
基文、磁性材料読本、工業調査会、１９９８）。The silicon content of the Fe—Si alloy powder is 5
It is preferably about 7% by weight. 5w silicon content
If it is less than t%, it is easily corroded by oxygen and the like,
It is not preferable because the radio wave absorbing property and the thermal conductivity are reduced. On the other hand, when the silicon content exceeds 7 wt%, Fe-
It is not preferable because the Si alloy powder becomes hard and brittle and becomes difficult to process. The Fe-Si alloy has a silicon content of 6%.
It has been reported that the crystal magnetic anisotropy and the magnetostriction constant both become close to 0 and exhibit high magnetic permeability at about wt% (Honma Motofumi, Magnetic Materials Reader, Industrial Research Institute, 1998).
【００１８】Ｆｅ−Ｓｉ合金粉末の平均粒子径（鱗片状
などの異方形状の場合は長径）は、１〜５０μｍである
ことが好ましい。平均粒子径が１μｍ未満では、かさ比
重が増えるため、有機マトリックス中に均一に分散させ
難くなり好ましくない。一方、平均粒子径が５０μｍを
超えると、準マイクロ波帯以上の電磁波の減衰に関与す
る軟磁性体粉末の表皮部分（およそ数μｍ）に対して、
電磁波の減衰に関与しない軟磁性体粉末の表皮以外の部
分（コア部分）の占有割合が大きくなり、Ｆｅ−Ｓｉ合
金粉末を高配合しても電波吸収特性を効率的に向上させ
ることができなくなる。The average particle diameter of the Fe-Si alloy powder (the long diameter in the case of an anisotropic shape such as a scale) is preferably 1 to 50 μm. When the average particle size is less than 1 μm, the bulk specific gravity increases, and it is difficult to uniformly disperse the particles in the organic matrix, which is not preferable. On the other hand, if the average particle size exceeds 50 μm, the skin portion (approximately several μm) of the soft magnetic material powder that is involved in attenuation of electromagnetic waves in the quasi-microwave band or more is
The occupation ratio of a portion (core portion) other than the skin of the soft magnetic material powder which does not contribute to the attenuation of the electromagnetic wave becomes large, and even if the Fe-Si alloy powder is highly blended, the radio wave absorption characteristics cannot be efficiently improved. .
【００１９】Ｆｅ−Ｓｉ合金粉末の配合割合は、５〜７
０ｖｏｌ％であることが好ましい。Ｆｅ−Ｓｉ合金粉末
の配合割合が５ｖｏｌ％未満では、十分な電波吸収特性
が得られ難く、また、その他の軟磁性体粉末を併用して
電波吸収特性を向上させた場合は熱伝導性が悪くなるた
め好ましくない。一方、Ｆｅ−Ｓｉ合金粉末の配合割合
が７０ｖｏｌ％を超えると、熱伝導性充填剤を有機マト
リックス中に高配合することができなくなり、熱伝導性
が低下するため好ましくない。The mixing ratio of the Fe—Si alloy powder is 5-7.
It is preferably 0 vol%. If the mixing ratio of the Fe—Si alloy powder is less than 5 vol%, it is difficult to obtain sufficient radio wave absorption characteristics, and if the soft magnetic material powder is used in combination to improve the radio wave absorption characteristics, thermal conductivity is poor. Is not preferred. On the other hand, if the compounding ratio of the Fe—Si alloy powder exceeds 70 vol%, it is not preferable because the thermal conductive filler cannot be highly blended in the organic matrix, and the thermal conductivity decreases.
【００２０】なお、Ｆｅ−Ｓｉ合金粉末は、有機マトリ
ックスとの相溶性、分散性等を改善するために、必要に
応じてシランカップリング剤、チタネートカップリング
剤等により表面処理されたものであっても構わない。The Fe—Si alloy powder has been subjected to a surface treatment with a silane coupling agent, a titanate coupling agent or the like, if necessary, in order to improve the compatibility and dispersibility with the organic matrix. It does not matter.
【００２１】[0021]
【発明の実施の形態】以下、本発明を具現化した放熱性
電波吸収シート（放熱性電波吸収体）について説明す
る。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a heat-radiating radio wave absorbing sheet (heat-radiating radio wave absorber) embodying the present invention will be described.
【００２２】放熱性電波吸収シートは、有機マトリック
ス中に、熱伝導性充填剤と上述した軟磁性体粉末として
のＦｅ−Ｓｉ合金粉末とを含有する混合組成物を、シー
ト状に成形してなる。The heat-dissipating radio wave absorbing sheet is formed by molding a mixed composition containing a heat conductive filler and the above-mentioned Fe-Si alloy powder as the soft magnetic material powder in an organic matrix. .
【００２３】有機マトリックスは、機械的強度、耐熱
性、電気的特性、耐久性など各種使用性能に応じて公知
の有機マトリックス、例えば、樹脂、ゲル、ゴム、熱可
塑性エラストマーなどから適宜選択して用いることがで
き、その組成や硬化形態等について特に限定されるもの
ではない。電子部品への接着性、追従性等を考慮する
と、有機マトリックスはシリコーンゲルであることが好
ましい。なお、有機マトリックスは、一種を単独で用い
たものであっても、ブレンドにより二種以上を併用した
ものであっても構わず、また、アロイ化されたものであ
っても差し支えない。The organic matrix is appropriately selected from known organic matrices, for example, resins, gels, rubbers, thermoplastic elastomers, etc., according to various use performances such as mechanical strength, heat resistance, electrical characteristics, and durability. There is no particular limitation on the composition, curing form and the like. The organic matrix is preferably a silicone gel in consideration of adhesiveness to an electronic component, followability, and the like. In addition, the organic matrix may be used alone or in combination of two or more by blending, and may be alloyed.
【００２４】熱伝導性充填剤は、特に限定されるもので
はないが、熱伝導性の良好な酸化アルミニウム、酸化亜
鉛、窒化アルミニウム、窒化ホウ素、窒化ケイ素、炭化
ケイ素、石英、水酸化アルミニウムなどの金属酸化物、
金属窒化物、金属炭化物、金属水酸化物や、銀、銅、
金、鉄、アルミニウム、マグネシウムなどの金属や合金
などを好適に用いることができる。また、熱伝導性充填
剤の粒子形状、粒子径等は特に限定されるものではな
い。さらに、熱伝導性充填剤は、有機マトリックスとの
相溶性や分散性等を改善するために、必要に応じてシラ
ンカップリング剤、チタネートカップリング剤等により
表面処理されたものであっても構わない。The heat conductive filler is not particularly limited, but is preferably a heat conductive filler such as aluminum oxide, zinc oxide, aluminum nitride, boron nitride, silicon nitride, silicon carbide, quartz, aluminum hydroxide, etc. Metal oxides,
Metal nitride, metal carbide, metal hydroxide, silver, copper,
Metals and alloys such as gold, iron, aluminum, and magnesium can be suitably used. Further, the particle shape, particle diameter, and the like of the thermally conductive filler are not particularly limited. Furthermore, the heat conductive filler may be one that has been surface-treated with a silane coupling agent, a titanate coupling agent, or the like, if necessary, in order to improve compatibility, dispersibility, and the like with the organic matrix. Absent.
【００２５】放熱性電波吸収シートの厚さは、０．２〜
５ｍｍであることが好ましい。０．２ｍｍよりも薄い
と、製造し難くなるとともに、十分な電波吸収特性が得
られなくなる。一方、５ｍｍよりも厚いと、熱伝導性が
低下しかつ高価格になるので好ましくない。The thickness of the heat-dissipating radio wave absorbing sheet is from 0.2 to
It is preferably 5 mm. If the thickness is less than 0.2 mm, it becomes difficult to manufacture, and sufficient radio wave absorption characteristics cannot be obtained. On the other hand, when the thickness is more than 5 mm, the thermal conductivity is reduced and the cost becomes high, which is not preferable.
【００２６】また、放熱性電波吸収シートは、少なくと
も一方のシート表面が接着性を有するものであることが
好ましい。電子部品と充分に密着させることができ、伝
熱面積をより多く確保して物理的に熱伝導性を向上させ
ることができるとともに、電磁波の漏れを少なくするこ
とができる。It is preferable that at least one of the heat-radiating radio wave absorbing sheets has an adhesive property. It is possible to sufficiently adhere to the electronic component, to secure more heat transfer area and physically improve thermal conductivity, and to reduce leakage of electromagnetic waves.
【００２７】さらに、放熱性電波吸収シートは、作業性
向上や補強、電磁波のシールド等を目的として、いずれ
か一方のシート表面又はシート内に、シート状或いは繊
維状の補強層やシールド層などが積層或いは埋設された
ものであっても構わない。Further, the heat-radiating electromagnetic wave absorbing sheet has a sheet-like or fibrous reinforcing layer or a shielding layer on one of the sheet surfaces or in the sheet for the purpose of improving workability, reinforcing, shielding electromagnetic waves, and the like. They may be stacked or buried.
【００２８】なお、放熱性電波吸収シートは、上述した
軟磁性体粉末及び熱伝導性充填剤のほかに、他の添加剤
などを含んでいても良く、例えば、可塑剤、粘着剤、補
強剤、着色剤、耐熱向上剤等を含有したものであっても
構わない。また、上述したＦｅ−Ｓｉ合金粉末ととも
に、他の軟磁性体粉末を併用しても構わない。他の軟磁
性体粉末としては、例えば、Ｆｅ−Ｓｉ−Ａｌ合金（セ
ンダスト）粉末、Ｆｅ−Ｎｉ合金（パーマロイ）粉末、
Ｍｎ−Ｚｎフェライト粉末、Ｎｉ−Ｚｎフェライト粉
末、Ｍｇ−Ｚｎフェライト粉末等が挙げられる。The heat-dissipating radio wave absorbing sheet may contain other additives in addition to the soft magnetic powder and the heat conductive filler described above. For example, a plasticizer, an adhesive, a reinforcing agent, etc. , A colorant, a heat resistance improver, and the like. Further, other soft magnetic material powders may be used in combination with the above-described Fe-Si alloy powder. Other soft magnetic powders include, for example, Fe—Si—Al alloy (Sendust) powder, Fe—Ni alloy (Permalloy) powder,
Mn-Zn ferrite powder, Ni-Zn ferrite powder, Mg-Zn ferrite powder and the like can be mentioned.
【００２９】以上詳述したように、本実施形態によれば
以下に示す作用効果が奏される。・ 軟磁性体粉末とし
て、Ｆｅ−Ｓｉ合金粉末を用いた。このようにＦｅ−Ｓ
ｉ合金粉末を用いることにより、優れた熱伝導性を有す
るとともに、準マイクロ波帯以上の高周波数帯域、特に
１ＧＨｚ以上の高周波数帯域において優れた電波吸収特
性を有する放熱性電波吸収シートを実現することができ
る。従って、この放熱性電波吸収シートは、近年利用が
増加している準マイクロ波帯以上の高周波数帯域を利用
する電子機器の各種電子部品、例えば、電磁波を発生す
る電子部品、電磁波により干渉を受ける電子部品、或い
は熱を発生する電子部品等に好適に用いることができ
る。As described in detail above, according to the present embodiment, the following operational effects can be obtained. -Fe-Si alloy powder was used as the soft magnetic material powder. Thus, Fe-S
By using the i-alloy powder, a heat-dissipating radio wave absorption sheet having excellent heat conductivity and excellent radio wave absorption characteristics in a high frequency band above the quasi-microwave band, particularly in a high frequency band above 1 GHz is realized. be able to. Therefore, the heat-dissipating radio wave absorbing sheet is subject to interference by various electronic components of an electronic device using a high frequency band higher than the quasi-microwave band, for example, an electronic component that generates an electromagnetic wave, and an electromagnetic wave. It can be suitably used for an electronic component or an electronic component that generates heat.
【００３０】・ Ｆｅ−Ｓｉ合金粉末のケイ素含有量
を、５〜７ｗｔ％とした。ケイ素含有量が５〜７ｗｔ％
のＦｅ−Ｓｉ合金は透磁率及び耐腐食性に優れているこ
とから、これを軟磁性体粉末として用いることにより、
電波吸収特性及び耐候性に優れた放熱性電波吸収シート
を実現することができる。The silicon content of the Fe—Si alloy powder was 5 to 7 wt%. Silicon content is 5-7wt%
Fe-Si alloy is excellent in magnetic permeability and corrosion resistance, so by using this as a soft magnetic powder,
A heat-dissipating radio wave absorption sheet having excellent radio wave absorption characteristics and weather resistance can be realized.
【００３１】・ Ｆｅ−Ｓｉ合金粉末の平均粒子径を、
１〜５０μｍとした。このようにＦｅ−Ｓｉ合金粉末の
平均粒子径を１〜５０μｍとすると、有機マトリックス
に対する分散性が良好となるため、Ｆｅ−Ｓｉ合金粉末
を有機マトリックス中に高充填して電波吸収特性及び熱
伝導性に優れた放熱性電波吸収シートを実現することが
できる。The average particle diameter of the Fe—Si alloy powder is
The thickness was 1 to 50 μm. When the average particle diameter of the Fe—Si alloy powder is 1 to 50 μm, the dispersibility in the organic matrix becomes good. It is possible to realize a heat-dissipating radio wave absorbing sheet having excellent properties.
【００３２】・ Ｆｅ−Ｓｉ合金粉末の配合割合を、５
〜７０ｖｏｌ％とした。このようにＦｅ−Ｓｉ合金粉末
の配合割合を５〜７０ｖｏｌ％とすることにより、電波
吸収性特性及び熱伝導性に優れた放熱性電波吸収シート
を実現することができる。The compounding ratio of the Fe—Si alloy powder is 5
７０70 vol%. By setting the mixing ratio of the Fe-Si alloy powder to 5 to 70 vol%, a heat-radiating radio wave absorbing sheet having excellent radio wave absorbing properties and thermal conductivity can be realized.
【００３３】・ 有機マトリックスとして、シリコーン
ゲルを用いた。このように接着性及び追従性に優れるシ
リコーンゲルを用いると、電子部品と充分に密着させ
て、伝熱面積をより多く確保することができるとともに
電磁波の漏れを少なくすることができる。従って、高密
度実装化された近年の高性能な電子部品等に好適に用い
ることができる、電波吸収特性及び熱伝導性に優れた放
熱性電波吸収シートを実現することができる。A silicone gel was used as the organic matrix. When a silicone gel having excellent adhesiveness and followability is used, the silicone gel can be sufficiently adhered to an electronic component, so that a larger heat transfer area can be secured and leakage of electromagnetic waves can be reduced. Therefore, it is possible to realize a heat-dissipating radio wave absorption sheet having excellent radio wave absorption characteristics and thermal conductivity, which can be suitably used for a recent high-performance electronic component or the like which is mounted at a high density.
【００３４】・ 有機マトリックス中に熱伝導性充填剤
と上述した軟磁性体粉末としてＦｅ−Ｓｉ合金粉末とを
含有する混合組成物を、シート状に成形した。このよう
にシート状の放熱性電波吸収体とすることにより、例え
ば、電子部品の側面から上面を覆うように装着したり、
或いは複数の電子部品を覆うように装着することができ
るため、部品点数の減少させることができるとともに、
電磁波ノイズの減衰及び発熱部品の放熱をより高効率で
行なうことができるようになる。A mixed composition containing a thermally conductive filler in an organic matrix and the above-described Fe—Si alloy powder as a soft magnetic powder was formed into a sheet. By using a sheet-like heat-dissipating radio wave absorber in this way, for example, the electronic component can be mounted so as to cover the side surface from the top surface,
Alternatively, since it can be mounted so as to cover a plurality of electronic components, the number of components can be reduced,
Attenuation of electromagnetic wave noise and heat radiation of heat-generating components can be performed with higher efficiency.
【００３５】[0035]
【実施例】以下、実施例及び比較例を挙げて前記実施形
態をさらに具体的に詳細に説明するが、これらは本発明
の範囲を何ら制限するものではない。EXAMPLES Hereinafter, the above embodiments will be described in more detail with reference to Examples and Comparative Examples, but these do not limit the scope of the present invention in any way.
【００３６】なお、各実施例及び比較例の放熱性電波吸
収シートの電波吸収特性は、ネットワークアナライザ
（ＨＰ製８７２０）を用いて反射係数及び透過係数を測
定し、そこから反射減衰量を求めたものである。また、
各実施例及び比較例の放熱性電波吸収シートの熱伝導率
は、迅速熱伝導率計（京都電子工業株式会社製ＱＴＭ−
５００）にて測定したものである。さらに、各実施例及
び比較例の混合組成物の粘度は、回転粘度計にて測定し
たものである。The radio wave absorption characteristics of the heat-radiating radio wave absorbing sheets of the respective examples and comparative examples were obtained by measuring the reflection coefficient and the transmission coefficient using a network analyzer (8720 made by HP) and calculating the return loss therefrom. Things. Also,
The thermal conductivity of the heat-dissipating radio wave absorbing sheet of each example and comparative example was measured using a rapid thermal conductivity meter (QTM-
500). Further, the viscosities of the mixed compositions of the respective Examples and Comparative Examples were measured with a rotational viscometer.
【００３７】（実施例１）有機マトリックスとして付加
型の液状シリコーンゲル（東レ・ダウコーニング・シリ
コーン社製 比重１．０）１００重量部に、軟磁性体粉
末としてケイ素含有量が６ｗｔ％のＦｅ−Ｓｉ合金粉末
（真比重７．１、平均粒子径１０μｍ）９００重量部
と、熱伝導性充填剤として炭化ケイ素（ＳｉＣ）粉末
（真比重３．１、平均粒子径６０μｍ）２７５重量部と
を配合し、攪拌脱泡機を用いて均一になるまで混合攪拌
して、混合組成物（シリコーンゲル組成物）を調整し
た。この混合組成物の配合割合は、有機マトリックス３
２ｖｏｌ％、炭化ケイ素粉末２８ｖｏｌ％、Ｆｅ−Ｓｉ
合金粉末４０ｖｏｌ％である。次いで、この混合組成物
を１２０℃で３０分加熱硬化させて、厚さ１ｍｍの放熱
性電波吸収シートを製造した。Example 1 As an organic matrix, 100 parts by weight of an addition type liquid silicone gel (Dow Corning Silicone Toray Co., Ltd., specific gravity: 1.0) was added as a soft magnetic powder to an Fe-containing powder having a silicon content of 6 wt%. 900 parts by weight of Si alloy powder (true specific gravity 7.1, average particle diameter 10 μm) and 275 parts by weight of silicon carbide (SiC) powder (true specific gravity 3.1, average particle diameter 60 μm) as a heat conductive filler Then, the mixture was mixed and stirred using a stirring and defoaming machine until the mixture became uniform to prepare a mixed composition (silicone gel composition). The mixing ratio of this mixed composition is
2 vol%, silicon carbide powder 28 vol%, Fe-Si
The alloy powder is 40 vol%. Next, this mixed composition was cured by heating at 120 ° C. for 30 minutes to produce a heat-radiating radio wave absorbing sheet having a thickness of 1 mm.
【００３８】（実施例２）軟磁性体粉末としてケイ素含
有量が７ｗｔ％のＦｅ−Ｓｉ合金粉末（平均粒子径１０
μｍ）を用いたほかは、上記実施例１と同様に混合組成
物を調整し、放熱性電波吸収シートを製造した。Example 2 As a soft magnetic material powder, an Fe—Si alloy powder having a silicon content of 7 wt% (average particle diameter of 10%) was used.
μm), a mixed composition was prepared in the same manner as in Example 1 to produce a heat-radiating electromagnetic wave absorbing sheet.
【００３９】（実施例３）軟磁性体粉末としてケイ素含
有量が６ｗｔ％のＦｅ−Ｓｉ合金粉末（平均粒子径３μ
ｍ）を用いたほかは、上記実施例１と同様に混合組成物
を調整し、放熱性電波吸収シートを製造した。Example 3 As a soft magnetic material powder, an Fe—Si alloy powder having a silicon content of 6 wt% (average particle diameter 3 μm)
Except for using m), a mixed composition was prepared in the same manner as in Example 1 to produce a heat-radiating electromagnetic wave absorbing sheet.
【００４０】（実施例４）軟磁性体粉末としてケイ素含
有量が６ｗｔ％のＦｅ−Ｓｉ合金粉末（平均粒子径５０
μｍ）を用いたほかは、上記実施例１と同様に混合組成
物を調整し、放熱性電波吸収シートを製造した。Example 4 Fe--Si alloy powder having a silicon content of 6 wt% (average particle diameter 50
μm), a mixed composition was prepared in the same manner as in Example 1 to produce a heat-radiating electromagnetic wave absorbing sheet.
【００４１】（実施例５）配合割合を、有機マトリック
ス３２ｖｏｌ％、炭化ケイ素粉末６３ｖｏｌ％、Ｆｅ−
Ｓｉ合金粉末５ｖｏｌ％としたほかは、上記実施例１と
同様に混合組成物を調整し、放熱性電波吸収シートを製
造した。Example 5 The mixing ratio was 32 vol% of organic matrix, 63 vol% of silicon carbide powder, Fe-
A mixed composition was prepared in the same manner as in Example 1 except that the Si alloy powder was 5 vol%, to produce a heat-radiating electromagnetic wave absorbing sheet.
【００４２】（実施例６）配合割合を、有機マトリック
ス３２ｖｏｌ％、炭化ケイ素粉末４８ｖｏｌ％、Ｆｅ−
Ｓｉ合金粉末２０ｖｏｌ％としたほかは、上記実施例１
と同様に混合組成物を調整し、放熱性電波吸収シートを
製造した。Example 6 The mixing ratio was 32 vol% of organic matrix, 48 vol% of silicon carbide powder, Fe-
Example 1 except that the Si alloy powder was 20 vol%.
The mixed composition was prepared in the same manner as described above to produce a heat-radiating radio wave absorbing sheet.
【００４３】（実施例７）配合割合を、有機マトリック
ス３２ｖｏｌ％、炭化ケイ素粉末８ｖｏｌ％、Ｆｅ−Ｓ
ｉ合金粉末６０ｖｏｌ％としたほかは、上記実施例１と
同様に混合組成物を調整し、放熱性電波吸収シートを製
造した。Example 7 The mixing ratio was 32 vol% of organic matrix, 8 vol% of silicon carbide powder, Fe-S
A mixed composition was prepared in the same manner as in Example 1 except that the i-alloy powder was 60 vol%, to produce a heat-radiating radio wave absorbing sheet.
【００４４】（比較例１）軟磁性体粉末としてＭｎ−Ｚ
ｎ系フェライト粉末（平均粒子径が３μｍ）を用いたほ
かは、上記実施例１と同様に混合組成物を調整し、放熱
性電波吸収シートを製造した。(Comparative Example 1) Mn-Z as a soft magnetic powder
Except for using n-type ferrite powder (average particle diameter is 3 μm), a mixed composition was prepared in the same manner as in Example 1 to produce a heat-radiating radio wave absorbing sheet.
【００４５】（比較例２）軟磁性体粉末としてケイ素含
有量が４．５ｗｔ％のＦｅ−Ｓｉ合金粉末（平均粒子径
１０μｍ）を用いたほかは、上記実施例１と同様に混合
組成物を調整し、放熱性電波吸収シートを製造した。Comparative Example 2 A mixed composition was prepared in the same manner as in Example 1 except that an Fe—Si alloy powder having a silicon content of 4.5 wt% (average particle diameter: 10 μm) was used as the soft magnetic material powder. After adjustment, a heat-radiating electromagnetic wave absorbing sheet was manufactured.
【００４６】（比較例３）軟磁性体粉末を配合せずに、
配合割合を有機マトリックス３２ｖｏｌ％、炭化ケイ素
粉末６８ｖｏｌ％としたほかは、上記実施例１と同様に
混合組成物を調整し、放熱性電波吸収シートを製造し
た。(Comparative Example 3) Without blending the soft magnetic powder,
Except that the mixing ratio was 32 vol% of the organic matrix and 68 vol% of the silicon carbide powder, the mixed composition was adjusted in the same manner as in Example 1 to produce a heat-radiating radio wave absorbing sheet.
【００４７】上記各実施例及び比較例の混合組成物の２
５℃における粘度、及び放熱性電波吸収シートの熱伝導
率の測定結果を表１及び表２に示す。また、各実施例及
び比較例の放熱性電波吸収シートの反射減衰量の測定結
果を図１〜図３に示す。Each of the mixed compositions of Examples and Comparative Examples 2
Tables 1 and 2 show the measurement results of the viscosity at 5 ° C. and the thermal conductivity of the heat-radiating electromagnetic wave absorbing sheet. In addition, FIGS. 1 to 3 show the measurement results of the return loss of the heat-dissipating radio wave absorbing sheets of the examples and the comparative examples.
【００４８】[0048]
【表１】 [Table 1]
【００４９】[0049]
【表２】 [Table 2]
【００５０】（考察）Ｆｅ−Ｓｉ合金粉末を用いた実施
例１〜実施例７の放熱性電波吸収シートは、いずれも準
マイクロ波帯以上の高周波数帯域、特に１ＧＨｚ以上の
高周波数帯域において優れた電波吸収特性を有すること
が確認され、準マイクロ波帯以上の高周波数帯域に整合
した電波吸収シートであることが確認された。また、実
施例１〜実施例７の放熱性電波吸収シートは、いずれも
熱伝導率が２．０（Ｗ／（ｍ・Ｋ））以上を示し、優れ
た熱伝導性を有することが確認された。(Discussion) The heat-radiating electromagnetic wave absorbing sheets of Examples 1 to 7 using the Fe-Si alloy powder are all excellent in a high frequency band above the quasi-microwave band, particularly in a high frequency band above 1 GHz. It was confirmed that the sheet had an improved electromagnetic wave absorption characteristic, and that it was a radio wave absorption sheet matched to a high frequency band equal to or higher than the quasi-microwave band. Further, the heat-radiating radio wave absorbing sheets of Examples 1 to 7 all have a thermal conductivity of 2.0 (W / (m · K)) or more, and have been confirmed to have excellent thermal conductivity. Was.
【００５１】一方、従来技術であるＭｎ−Ｚｎ系フェラ
イト粉末を用いた比較例１の放熱性電波吸収シートは、
実施例１〜実施例７の放熱性電波吸収シートと比較し
て、電波吸収特性及び熱伝導性ともに劣る。また、ケイ
素含有量が４．５ｗｔ％のＦｅ−Ｓｉ合金粉末を用いた
比較例２の放熱性電波吸収シートは、電波吸収特性及び
熱伝導性ともに良好であったが、Ｆｅ−Ｓｉ合金の酸化
が進行しやすいため経時的な電波吸収特性と熱伝導性の
劣化が懸念される。さらに、Ｆｅ−Ｓｉ合金粉末を配合
しなかった比較例３の放熱性電波吸収シートは、熱伝導
性は良好であったが、電波吸収特性が全く見られなかっ
た。On the other hand, the heat-radiating radio wave absorbing sheet of Comparative Example 1 using the conventional Mn-Zn ferrite powder is:
As compared with the heat dissipation radio wave absorbing sheets of Examples 1 to 7, both the radio wave absorption characteristics and the thermal conductivity are inferior. Further, the heat-radiating radio wave absorbing sheet of Comparative Example 2 using the Fe-Si alloy powder having a silicon content of 4.5 wt% had good radio wave absorbing properties and thermal conductivity, but the oxidation of the Fe-Si alloy was Is likely to proceed, and there is a concern that radio wave absorption characteristics and thermal conductivity may deteriorate over time. Further, the heat dissipation radio wave absorbing sheet of Comparative Example 3 in which no Fe-Si alloy powder was blended had good thermal conductivity, but did not show any radio wave absorption characteristics.
【００５２】次に、上記実施形態、実施例及び比較例よ
り把握される技術的思想について記載する。 （Ａ） 熱伝導率が、２．０（Ｗ／（ｍ・Ｋ））以上で
あることを特徴とする請求項１から請求項５のいずれか
１項に記載の放熱性電波吸収体。Next, technical ideas grasped from the above embodiment, examples and comparative examples will be described. (A) The heat-dissipating radio wave absorber according to any one of claims 1 to 5, wherein the heat conductivity is 2.0 (W / (m · K)) or more.
【００５３】（Ｂ） 有機マトリックス中に、軟磁性体
粉末と熱伝導性充填剤とを含有する混合組成物であっ
て、軟磁性体粉末がＦｅ−Ｓｉ合金粉末であることを特
徴とする混合組成物。 （Ｃ） 軟磁性体粉末が、ケイ素含有量５〜７ｗｔ％の
Ｆｅ−Ｓｉ合金粉末であることを特徴とする上記（Ｂ）
に記載の混合組成物。 （Ｄ） Ｆｅ−Ｓｉ合金粉末の平均粒子径が、１〜５０
μｍであることを特徴とする上記（Ｂ）又は（Ｃ）に記
載の混合組成物。 （Ｅ） Ｆｅ−Ｓｉ合金粉末の配合割合が、５〜７０ｖ
ｏｌ％であることを特徴とする上記（Ｂ）から（Ｄ）の
いずれか１に記載の混合組成物。 （Ｆ） 有機マトリックスが、シリコーンゲルであるこ
とを特徴とする上記（Ｂ）から（Ｅ）のいずれか１に記
載のシリコーンゲル組成物。(B) A mixed composition comprising a soft magnetic material powder and a thermally conductive filler in an organic matrix, wherein the soft magnetic material powder is an Fe-Si alloy powder. Composition. (C) The soft magnetic material powder is an Fe—Si alloy powder having a silicon content of 5 to 7 wt%, wherein (B)
3. The mixed composition according to item 1. (D) The average particle diameter of the Fe—Si alloy powder is 1 to 50.
The mixed composition according to the above (B) or (C), wherein the composition is μm. (E) The compounding ratio of the Fe—Si alloy powder is 5 to 70 v
ol%, the mixed composition according to any one of the above (B) to (D). (F) The silicone gel composition according to any one of the above (B) to (E), wherein the organic matrix is a silicone gel.
【００５４】（Ｇ） 上記（Ｂ）から（Ｆ）のいずれか
１に記載の混合組成物を、所定形状に成形してなる放熱
性電波吸収体。 （Ｈ） 上記（Ｂ）から（Ｆ）のいずれか１に記載の混
合組成物を、シート状に成形してなる放熱性電波吸収シ
ート。(G) A heat-radiating radio wave absorber formed by molding the mixed composition according to any one of (B) to (F) into a predetermined shape. (H) A heat-radiating electromagnetic wave absorbing sheet obtained by molding the mixed composition according to any one of (B) to (F) into a sheet.
【００５５】[0055]
【発明の効果】以上に詳述したように、本発明によれ
ば、軟磁性体粉末としてＦｅ−Ｓｉ合金粉末を用いるこ
とにより、優れた熱伝導性を有するとともに、準マイク
ロ波帯以上の高周波数帯域、特に１ＧＨｚ以上の高周波
数帯域において優れた電波吸収特性を有する放熱性電波
吸収体を実現することができる。As described in detail above, according to the present invention, the use of the Fe--Si alloy powder as the soft magnetic material powder has not only excellent thermal conductivity but also a high quasi-microwave band or higher. It is possible to realize a heat-dissipating radio wave absorber having excellent radio wave absorption characteristics in a frequency band, particularly a high frequency band of 1 GHz or more.
【００５６】そして本発明の放熱性電波吸収体は、準マ
イクロ波帯以上の高周波数帯域に整合したものであり、
電磁波ノイズの減衰及び放熱をより高効率で行うことが
できることから、近年利用が増加している準マイクロ波
帯以上の高周波数帯域を利用する電子機器に対応する放
熱性電波吸収体として非常に有用なものである。The heat-dissipating radio wave absorber of the present invention is matched to a high frequency band equal to or higher than the quasi-microwave band.
Very useful as a heat-dissipating radio wave absorber for electronic devices that use high-frequency bands above the quasi-microwave band, which have been increasingly used in recent years, because they can attenuate and dissipate electromagnetic wave noise with higher efficiency. It is something.
【図１】 実施例１、実施例２、比較例１及び比較例２
の放熱性電波吸収シートの反射減衰量を示すグラフ。FIG. 1 Example 1, Example 2, Comparative Example 1, and Comparative Example 2
5 is a graph showing the return loss of the heat-dissipating radio wave absorption sheet of FIG.
【図２】 実施例１、実施例３及び実施例４の放熱性電
波吸収シートの反射減衰量を示すグラフ。FIG. 2 is a graph showing the return loss of the heat-radiating radio wave absorbing sheets of Examples 1, 3 and 4.
【図３】 実施例１、実施例５〜実施例７及び比較例３
の放熱性電波吸収シートの反射減衰量を示すグラフ。FIG. 3 Example 1, Example 5 to Example 7, and Comparative Example 3
5 is a graph showing the return loss of the heat-dissipating radio wave absorption sheet of FIG.
Claims (5)
伝導性充填剤とを含有する混合組成物を、所定形状に成
形してなる放熱性電波吸収体であって、 軟磁性体粉末が、Ｆｅ−Ｓｉ合金粉末であることを特徴
とする放熱性電波吸収体。1. A heat-dissipating radio wave absorber formed by molding a mixed composition containing a soft magnetic powder and a thermally conductive filler in an organic matrix into a predetermined shape, wherein the soft magnetic powder comprises: A heat-dissipating radio wave absorber, which is an Fe-Si alloy powder.
５〜７ｗｔ％であることを特徴とする請求項１に記載の
放熱性電波吸収体。2. The Fe—Si alloy powder has a silicon content of:
The heat-dissipating radio wave absorber according to claim 1, wherein the content is 5 to 7 wt%.
〜５０μｍであることを特徴とする請求項１又は請求項
２に記載の放熱性電波吸収体。3. The average particle diameter of the Fe—Si alloy powder is 1
The heat-dissipating radio wave absorber according to claim 1, wherein the thickness is from 50 μm to 50 μm.
７０ｖｏｌ％であることを特徴とする請求項１から請求
項３のいずれか１項に記載の放熱性電波吸収体。4. The compounding ratio of the Fe—Si alloy powder is 5 to 5.
The heat-dissipating radio wave absorber according to any one of claims 1 to 3, wherein the content is 70 vol%.
あることを特徴とする請求項１から請求項４のいずれか
１項に記載の放熱性電波吸収体。5. The heat-dissipating radio wave absorber according to claim 1, wherein the organic matrix is a silicone gel.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001181871A JP2002374092A (en) | 2001-06-15 | 2001-06-15 | Heat dissipating radio wave absorber |
| EP02253729A EP1267601A3 (en) | 2001-06-15 | 2002-05-28 | Heat-radiating electromagnetic wave absorber |
| US10/171,130 US6716904B2 (en) | 2001-06-15 | 2002-06-13 | Heat-radiating electromagnetic wave absorber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001181871A JP2002374092A (en) | 2001-06-15 | 2001-06-15 | Heat dissipating radio wave absorber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002374092A true JP2002374092A (en) | 2002-12-26 |
Family
ID=19022072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001181871A Pending JP2002374092A (en) | 2001-06-15 | 2001-06-15 | Heat dissipating radio wave absorber |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US6716904B2 (en) |
| EP (1) | EP1267601A3 (en) |
| JP (1) | JP2002374092A (en) |
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Also Published As
| Publication number | Publication date |
|---|---|
| US20030008969A1 (en) | 2003-01-09 |
| EP1267601A2 (en) | 2002-12-18 |
| US6716904B2 (en) | 2004-04-06 |
| EP1267601A3 (en) | 2004-06-09 |
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